The Alpha / Beta / Omega personalities

I'm a sucker for personality tests (kind of feeds into that whole 'being a therapist' thing). I came across this article/assessment that goes over these different personality types. We hear a lot about alpha personalities (dominant, outgoing types), but less so about beta (more reserved, laid back) and the others. As for me, I think I'm an 'aspiring' alpha, maybe more gamma than alpha. How about you?